Consider me skeptical of the practical significance of their findings. IMO, protease inhibitors are a moot point if the they don't also block cell entry via antibody-dependent enhancement (ADE):
- http://viruseradication.com/abstract-details.php?abstract_id...
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6178114/
- https://jvi.asm.org/content/94/5/e02015-19.abstract
It's been a while since my vaccine research days at the NIH, so take my skepticism with a grain of salt.